Qi Ge likes to solve computation geometry problems. He writes n points on the paper, but he wants to find the number of different groups (A,B,C) such that point B is the middle of segment AC or CA. And segment AC,CA are considered to be the same. Your task is to calculate the number of such group.

There are several test cases. The first line contains a single integer n (3<=n<=3000)-the number of points. Next n lines contain the points. The i-th line contains coordinates of the i-th point: two space-separated integers xi,yi (-1000<=xi,yi<=1000). It is guaranteed that all given points are different.

Print the single number — the answer to the problem.

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